A new approach holding out great promise is the use of drug-coated stents. The most commonly mentioned are
sirolimus-coated stents, rapamycin-coated stents, and paclitaxel-coated stents.
At the Congress of the European Society of Cardiology in Stockholm, in the second week of September,
investigators reported early results from the RAVEL trial, a trial examining the efficacy of a drug-coated stent
made by Johnson & Johnson.
In the follow-up period of 210 days there was no restenosis in patients receiving the drug-coated stent in the
RAVEL trial.
Despite the remarkable early results with the sirolimus-coated stent, release of this product for general clinical
use is not expected until 2002 in Europe, and in 2003 in the United States. Whether these results are "too good to
be true", will only be determined over a period of several years.
In the aftermath of the recently reported clinical trials Johnson & Johnson has launched a new set of clinical
trials which include 35 medical centers in Europe and Israel. The two hospitals participating in Israel, are the
Hadassah Medical Center in Jerusalem and Haifa's Rambam Medical Center.
"The clinical trials that we are embarking on, are somewhat different then those reported on in Stockholm. First,
the stents will be somewhat smaller in diameter and the lesions being treated will be longer. Essentially, we will
be performing trials on patients who would tend to have a higher incidence of restenosis then the previous
group," explains Dr. Louis Gruberg, a participating cardiologist at the Invasive Cardiology Center at the Rambam
Medical Center, in Haifa. The results of the trials will be viewed initially after eight months and the study will
include a five year follow-up.
Prof. Rafael Beyar, the Israeli inventor of the stent, now serves as the Dean of the Technion Medical School,
continues to oversee a range of medical R & D projects.
The NIR Stent developed and produced by the Israeli Medinol Ltd. is marketed by the American Boston Scientific
company which commands about 30% of the American stent market.
According to a Morgan Stanley Dean Witter report on coronary stents, in 2000 770,000 angioplasty procedures
were carried out in the United States. Of these more than 80% or 624,000 included stents.
Clinical work currently being carried out in Israel and in European medical centers, will determine whether
medicated stents will assume the lead in a new generation of restenosis free cardiac treatment.
Nearly a year ago, the American Vice-President Richard Cheney, was admitted to the hospital with unstable
angina. As part of the care, he received a stent, but in March of this year he was found to have restenosis at the
site of his stent. Restenosis occurs within 3-6 months in 40- 50% of patients who have undergone
angioplasty. This incidence has been reduced to 20-30% with the use of stents. For most individuals, including
Vice-President Cheney, restenosis remains a major problem. A balloon is passed across an atherosclerotic
plaque in a coronary artery. The balloon is then inflated - thus compressing the plaque, and widening the
opening of the artery. Compression of the plaque is a far from a gentle process, and nearly always creates
trauma to the blood vessel wall. Restenosis is the formation of new blockages at the site of the angioplasty or
stent placement. It occurs within 3-6 months in 40-50% of the patients. There are two major mechanisms
responsible for restenosis. One of these is thrombosis, or clotting at the site of the treatment . The risk of its
occurrence is highest immediately after angioplasty and the condition is treatable with anti-clotting drugs. The
other issue is the growth of tissue at the site of the treatment. The use of "inhibitors" reduces this risk.
The possibility of restenosis during six months after the receipt of a stent is still as high as 50-70%.
The Israel High-Tech & Investment Report in 1992 obtained its first insights and information in angioplasty from
Prof. Hylton Miller, cardiologist and director of the catheterization unit at Tel-Aviv's Sourasky Medical Center. The
vision was then formed, that the rapidly developing field of stents, as an adjunct to conventional balloon
angioplasty, was well on its way to becoming one of the fastest growing fields among medical devices. Over the
years nearly every type of interventional angioplasty procedure has been carried out at the Sourasky Medical
Center. Approximately 1000 procedures are carried out yearl at the Center. Conventional stents can cost as
much as $1,000 each while the new coated stents may triple in cost.
Stent industry estimates put the annual world market for stents at $1.2 billion. However, this figure may increase
dramatically if the new stents gain an important segment of the total stent market.
Israeli medical researchers were at the forefront of medical stent research and development. IHTIR visited an
Israeli company named InStent Ltd., a subsidiary of InStent Inc.,a listed American company (NASDAQ:ININ). In
less than one year the New York Stock Exchange listed company Medtronic purchased InStent and InStent
investors, over a short period time, experienced a capital gain of $1.75 on each $1 worth of InStent shares.